<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>所有上边框属性在一条声明中</title>
</head>

<body>


    <style>
        p {
            border-top: 6px solid red;
            background-color: lightgrey;
        }
    </style>

    <p>这是段落中的一些文本。</p>
</body>

</html>